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Journal articles on the topic 'Test flakiness'
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1
Zhang, Hua Yong, Xiao Jian Liu, Hai Yan Sun, and Chun Sheng Fan. "A Sample Holder for X-Ray Powder Diffraction Studies of Flakiness and Block Sample." Key Engineering Materials 544 (March 2013): 433–36. http://dx.doi.org/10.4028/www.scientific.net/kem.544.433.
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Powder X-ray diffraction (XRD) is one of the primary techniques used to characterize solid state materials. But there is not a sample holder which can be fit into the sample carrier of the Bruker D8-Advance x-ray powder diffractometer for flakiness and block samples test. In this article, we will design, manufacture and evaluate a sample holder for flakiness and block samples. Materials of the holder are steel, glass and plasticine etc. The holder is low cost, easy to be processed, convenience to prepare the samples, and accurately obtain the best analytical results.
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Li, Yue Hong, Ping Zhang, and Bai Shou Li. "Research of Ductility and Crack of Square Steel Tube Regeneration Block Mixed Short Columns." Advanced Materials Research 608-609 (December 2012): 1764–68. http://dx.doi.org/10.4028/www.scientific.net/amr.608-609.1764.
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In order to analyze regeneration block mixed short columns and crack of recycled blocks, to flakiness ratio, mixing ratio, confinement coefficient and there are no ribs for the pilot study on main parameters, on root regeneration of thin-walled square tube 15 blocks of mixed axial compression test of short column. Research results indicates that: Specimen without ribs of ductility coefficient are going with flakiness ratio confinement coefficient of increases and reduces, approximate is linear relationship; and Specimen with rib short column of ductility coefficient are with flakiness ratio and confinement coefficient of increases and first increases then reduces, approximate is parabola relationship; internal concrete of Specimen without ribs of crack distribution concentrated in column Central, and internal concrete of Specimen with ribs of crack distribution along axis to more uniform, with ANSYS established model on internal concrete crack for nonlinear analysis. And experimental waist-shaped crease damaged concrete cracks occurred when parts of development corresponds to the situation.
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Jing, G. Q., Y. M. Ji, W. L. Qiang, and R. Zhang. "Experimental and Numerical Study on Ballast Flakiness and Elongation Index by Direct Shear Test." International Journal of Geomechanics 20, no. 10 (October 2020): 04020169. http://dx.doi.org/10.1061/(asce)gm.1943-5622.0001791.
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Nur Hidayah, A. H., Md Nor Hasanan, and P. J. Ramadhansyah. "Effect of Coarse Aggregate Sizes on Properties of Porous Concrete Paving Blocks." Advanced Materials Research 911 (March 2014): 433–37. http://dx.doi.org/10.4028/www.scientific.net/amr.911.433.
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Properties of Porous Concrete Paving Blocks (PCPB) were investigated in this study. Two groups of coarse aggregate sizes were performed; passing 8 mm retains 5 mm and passing 10 mm retains 8 mm. For mixture design, 100 % of coarse aggregate were used. However, fine aggregate was eliminated in this investigation. The density, water absorption, flakiness index and elongation index test were performed to determine the properties of the coarse aggregate used in this study. Compression test and skid resistance test were used to evaluate the performance of PCPB. The results show that PCPB containing coarse aggregate size 5 8 mm give high compressive strength compared to others PCPB specimen. In addition, both PCPB specimens give an in increasing in skid resistance approximately 30 % compared to Concrete Paving Blocks (CPB).
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Gonfa, Lami Gonfa, Emer Tucay Quezon Tucay Quezon, and Anteneh Geremew. "EXPERIMENTAL STUDY ON APPLICATION OF MARBLE WASTE AS CONVENTIONAL AGGREGATE FOR BASE COURSE MATERIALS." Journal of Civil Engineering, Science and Technology 11, no. 2 (September 30, 2020): 144–63. http://dx.doi.org/10.33736/jcest.2620.2020.
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Recently, highway and construction industries utilize a substantial quantity of conventional aggregates. The increasing demands for conventional aggregate cause an increase in the cost of construction, reduction of natural resource, and continuing deterioration of the earth's surface. On the other hand, the waste generated from the marble industries during the process of cutting and polishing was increasing day by day all over the world. In Ethiopia, the use of Marble Waste Aggregate materials in road construction as a base course material was not well-known, and it was simply wasted at every place where the marble production was continuing. Therefore, this paper focused on evaluating the possibility of using marble waste aggregate as conventional aggregate in the base course layer of flexible pavements by experimental method. To achieve the objectives of the research, mechanical stabilization and laboratory tests have been carried out at different percentage replacement of Conventional Aggregate by (0%, 20%, 40%, 50%, 60%, 80%, and 100%) of Marble Waste Aggregate weights. Marble wastes materials are collected from Burayyu city, Alisha marble processing industry. The laboratory test results for MWA indicated SG, ACV, AIV, LAA, Flakiness Index , Elongation Index, Plastic Index, Water Absorption, and CBR of 2.74%, 23.63%, 26.21%, 27.03%, 26.48%, 13.29%, Non Plastic, 0.50% and 73.3%, respectively. These test results fulfilled the ERA standard specification for some tests, and it showed marginal quality values to the standard specification for GB2 and GB3 base course materials. CBR and gradation test results shown failure to meet the standard specification. Thus, mechanical stabilization was done to improve the mechanical and physical properties of Marble Waste Aggregate. Blending of 80%MWA with 20% CA results in SG, ACV, AIV, LAA, Flakiness Index, Elongation Index, Plastic Index, Water Absorption, and CBR of 2.83%, 18.2%, 21.52%, 22.58%, 23.79%, 16.29%, Non Plastic, 0.80%,and 82.5% respectively. At this proportion the gradation also observed to fit with the required ERA standard specification of GB2 and GB3 materials. Therefore, the use of marble waste aggregate up to 80% by weight is recommended for road base course layer, when it is found near to the construction site and in places where the materials are abundantly available.
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Seyfe, M., and A. Geremew. "POTENTIAL USE OF CINDER GRAVEL AS AN ALTERNATIVE BASE COURSE MATERIAL THROUGH BLENDING WITH CRUSHED STONE AGGREGATE AND CEMENT TREATMENT." Journal of Civil Engineering, Science and Technology 10, no. 2 (September 29, 2019): 101–12. http://dx.doi.org/10.33736/jcest.1465.2019.
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Cinder gravels are pyroclastic materials associated with recent volcanic activity which occur in characteristically straight sided cone shaped hills. The aim of this study was to use this marginal material which is abundantly available in many parts of Ethiopia by modifying their properties through mechanical blending and chemical stabilization. Results of physical and mechanical test conducted on cinder gravel samples prove their marginality to be used as base course materials especially for highly trafficked roads. An experimental investigation were carried by blending cinder gravels with conventional crushed stone bases course material, Crushed Stone Aggregate (CSA), in proportions of cinder/ Crushed Stone Aggregate (CSA) (10/90, 20/80, 30/70, 40/60 and 50/50) and treating with 6. 8 and 10% of cement. According to results of sieve analysis, Aggregate crushing value (ACV), flakiness index and California Bearing Ratio (CBR), 30% of Crushed Stone Aggregate (CSA) can be replaced by cinder gravels for use as Fresh, crushed rock (GB1) material and for cement treated cinder gravels adding 6% and 8% cement make them suitable for use as Stabilized base course (CB2) and (CB1) base course materials respectively, referring to their 14 day compressive strength as determined by Unified compressive strength test(UCS) test.
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Oluwasola, E. A., A. Afolayan, O. O. Ipindola, M. O. Popoola, and A. O. Oginni. "Effect of Aggregate Shapes on the Properties of Concrete." LAUTECH Journal of Civil and Environmental Studies 5, no. 1 (September 27, 2020): 1–10. http://dx.doi.org/10.36108/laujoces/0202/50(0110).
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Aggregates constitute more than 90% of concrete and significantly determine the strength of concrete. In this study, the shape characteristics such as flakiness and elongation were determined using elongation and thickness gauge. The aggregate used for the study is granite. Aggregate crushing value and aggregate impact value tests were performed on the aggregate while slump test, water absorption test, compressive strength test and flexural strength test were carried out on concrete. A total of one hundred and thirty-two concrete cubes were produced using 1:2:4 and 1:3:6 mix each for the compressive strength test and forty-eight reinforced concrete beams were produced for flexural strength test. The slump for all the samples tested was examined to be true. The compressive strength of the concrete cube was greatly affected by the shape of aggregate used and it was noted that; for lower percentage of flaky and elongated aggregate the compressive strength is moderately high compared to when the percentage is high. The highest obtained compressive strength, 15N/mm2 is in compliance with the concrete compressive strength of normal 1:2:4 mix as stipulated in ASTM C109, Also, with 30% of elongated aggregate and 30% of flaky, the flexural strength of 7.03 N/mm2 was obtained. This shows that aggregate shape is a very important property of coarse aggregate that must be put into consideration in production of quality concrete for construction works.
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Alam, Muhammad, Javed Akhtar Qureshi, Garee Khan, Manzoor Ali, and Shaheen Shah. "The Evaluation of Geotechnical Properties of Precambrian Hazara Slates, Hazara-Kashmir Syntaxis, Azad Kashmir, Pakistan." International Journal of Economic and Environmental Geology 10, no. 2 (September 4, 2019): 129–33. http://dx.doi.org/10.46660/ijeeg.vol10.iss2.2019.273.
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The fold and thrust belt of the eastern Hazara division characterised the sedimentary rocks of Precambrian toPaleocene age. The sequence and formation of Precambrian signify the oldest rock unit as Hazara Slate. Geologicalmap of the study area was prepared at the scale of 1:75,000 for about 140 square kilometre area located inMuzaffarabad (Azad Kashmir) district and Lohargali of Abbottabad (Khyber Pakhtunkhwa) district. The lab analysisshows that it is not rational to use Hazara slates as aggregate material due to its mineral accumulation and composition.Los Angele’s Abrasion Value, Impact Value, Crushing Value, Specific Gravity, Water Absorption, Flakiness Index,Elongation Index, Porosity Value, California Bearing Ratio test and Grain Size Analysis were done and co-related withB.S standards and the parameters were deduced. It was observed that the mineral composition of Hazara Slates rangesfor illite, kaolinite, quartz and carbonate. Kaolinite and illite are clay minerals which haveswelling potential to causeconstruction material damage the material. The presence of Carbonate and Quartz gives strength to the material, but itspercentage is low. Reserves calculation of different localities was also done for the quarry development.
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Alam, Muhammad, Javed Akhtar Qureshi, Garee Khan, Manzoor Ali, and Shaheen Shah. "The Evaluation of Geotechnical Properties of Precambrian Hazara Slates, Hazara-Kashmir Syntaxis, Azad Kashmir, Pakistan." International Journal of Economic and Environmental Geology 10, no. 2 (September 4, 2019): 129–33. http://dx.doi.org/10.46660/ojs.v10i2.273.
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The fold and thrust belt of the eastern Hazara division characterised the sedimentary rocks of Precambrian toPaleocene age. The sequence and formation of Precambrian signify the oldest rock unit as Hazara Slate. Geologicalmap of the study area was prepared at the scale of 1:75,000 for about 140 square kilometre area located inMuzaffarabad (Azad Kashmir) district and Lohargali of Abbottabad (Khyber Pakhtunkhwa) district. The lab analysisshows that it is not rational to use Hazara slates as aggregate material due to its mineral accumulation and composition.Los Angele’s Abrasion Value, Impact Value, Crushing Value, Specific Gravity, Water Absorption, Flakiness Index,Elongation Index, Porosity Value, California Bearing Ratio test and Grain Size Analysis were done and co-related withB.S standards and the parameters were deduced. It was observed that the mineral composition of Hazara Slates rangesfor illite, kaolinite, quartz and carbonate. Kaolinite and illite are clay minerals which haveswelling potential to causeconstruction material damage the material. The presence of Carbonate and Quartz gives strength to the material, but itspercentage is low. Reserves calculation of different localities was also done for the quarry development.
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Ziao, J., and J. Tao. "Investigation of Interlaminar Defects and their Influence on Interlaminar Strength." Advanced Composites Letters 5, no. 4 (July 1996): 096369359600500. http://dx.doi.org/10.1177/096369359600500404.
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In this paper, we directed our attention to the interlaminar defects and their influence on the interlaminar strengths. With the aid of a S-570 scanning electron microscope, the morphology and distribution of interlaminar defects were inspected and documented. According to their shape, size and cause of formation, the defects were classified into five types: flakiness void, irregular shaped debond, local imperfectly cured resin, debond in two multi-directional plies, and inhomogeneous fibers and the large scale debond by these fibers. The cause of defects formation was discussed by analyzing the manufacturing process of composites. The influence of defects on the interlaminar strength and its mechanism was analyzed experimentally and theoretically. The results indicate that these defects, with different effects, decrease the interlaminar strength because they form interlaminar cracks, and the interlaminar shear strength is less affected than interlaminar tensile strength, which is measured according to GB4944 test method. To comprehend defects distribution effect, a four-point-bending test method was introduced to measure the interlaminar peel strength, and a discussion was made on the correlation between the interlaminar tensile strength, interlaminar peel strength and in-plane transverse tensile strength. Finally the concept of interlaminar defect coefficient, which can be used to characterize the defects, was set up and the formula to calculate it was proposed.
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Xirouchakis, D. "Correlations between mechanical and geometrical parameters in aggregates: a tool for quality assessment and control." Bulletin of the Geological Society of Greece 47, no. 4 (September 5, 2013): 2069. http://dx.doi.org/10.12681/bgsg.11091.
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Correlations between mechanical and geometrical parameters in aggregates can be used as quality and performance prediction tools. I evaluated the following parameter pairs: dry and wet resistance to wear (MDE & MDS), and resistance to fragmentation (LA); polishing resistance and abrasion (PSV–AAV); and flakiness and shape index (FI–SI). The data set comprises slags, sedimentary, igneous, and metamorphic rocks tested according to EN standard test methods. FI and SI are positively correlated (r = 0.83) and can be well described by the 1:1 line. Wet and dry resistance to wear are strongly correlated (r = 0.98) with MDE ≈ 2·MDS. Dry resistance to fragmentation (LA) and wet resistance to wear (MDE) are well correlated (r = 0.81), and can be described with the equation LA = 4.95×MDE 0,61 (R2 = 0.69). According to the PSV–AAV correlation, aggregates are divided into two groups with contrasting behavior. Limestones and slags (r = −0.49 to −0.69) exhibit high polishing for high abrasion resistance (high PSV–low AAV), whereas sandstones and mafic to intermediate volcanics (r = 0.44 to 0.39) exhibit high polishing for low abrasion resistance (high PSV–high AAV). Peridotites belong to either PSV–AAV group depending on the soft minerals.
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Gilang Trianugrah S, Bambang Wedyantadji, and Togi Nainggolan. "PEMANFAATAN LIMBAH PECAHAN BATU MARMER SEBAGAI PENGGANTI AGREGAT 10/10 PADA CAMPURAN AC-WC (ASPHALT CONCRETE – WEARING COURSE) TERHADAP NILAI KARAKTERISTIK MARSHALL." SONDIR 5, no. 1 (May 31, 2021): 32–39. http://dx.doi.org/10.36040/sondir.v5i1.3636.
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Keterbatasan material batu kali untuk campuran perkerasan lama kelamaan akan mengalami pengurangan. Dalam penelitian ini mengambil alternatif pemanfaatan limbah batu marmer sebagai pengganti agregat 10/10 pada campuran AC-WC. Di Kabupaten Tulungagung khususnya Desa Gamping Rejo mempunyai limbah batu marmer dari hasil pengolahan kerajinan yang hanya digunakan sebagai timbunan jalan berlubang dan kurang bernilai secara ekonomis.Penelitian ini bertujuan untuk mengetahui pengaruh limbah batu marmer sebagai pengganti agregat 10/10 ditinjau dari nilai karakteristik Marshall dan juga kelayakan dari limbah batu marmer. Kemudian melakukan pembuatan benda uji berjumlah 45 buah dilanjutkan dengan pengujian menggunakan metode Marshall Test di laboratorium bahan konstruksi Teknik Sipil Institut Teknologi Nasional Malang. Dari hasil pengujian Marshall sebelum dan sesudah menggunakan batu marmer didaptkan nilai Kadar Aspal Optimum sebesar (5,80%) dan (5,81%). Untuk kadar limbah pecahan batu marmer yang baik didapatkan pada variasi 25% dengan nilai karakteristik Marshall : Stabilitas (973,63 Kg), Flow (3,00 mm), VIM (3,99%), VMA (16,88%), VFA (76,36%), MQ (328,19 Kg/mm). Berdasarkan hasil pengujian batu marmer layak digunakan sebagai pengganti agregat 10/10 pada lapis AC-WC dengan nilai : Flakiness (20,04 %), Impact (12,98 %), Abrasi (27,26 %), Berat jenis (2,58), Penyerapan (1,43 %).
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Giannakopoulou, Panagiota, Petros Petrounias, Basilios Tsikouras, Stavros Kalaitzidis, Aikaterini Rogkala, Konstantin Hatzipanagiotou, and Stylianos Tombros. "Using Factor Analysis to Determine the Interrelationships between the Engineering Properties of Aggregates from Igneous Rocks in Greece." Minerals 8, no. 12 (December 8, 2018): 580. http://dx.doi.org/10.3390/min8120580.
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This paper investigates the interrelationships between the engineering properties of igneous aggregate rocks from Greece with the aid of the R-mode factor analysis. The collected samples represent mafic and ultramafic rocks from the ophiolite complexes of Gerania, Guevgueli, Veria-Naousa, and Edessa as well as intermediate-acidic rocks from the surrounding areas of the complexes. Factor analysis verifies the important interdependences among the engineering parameters like physical, mechanical, geometrical, and physicochemical properties by giving statistical significance. Variations of the petrographic characteristics of the investigated rocks influence their engineering properties as well as the interdependence among them. Factor 1, which is the most representative one (~36% of the total variance), shows interdependences between certain physical, mechanical, physicochemical properties such as total porosity (nt) with moisture content (w), nt with the Los Abrasion value (LA), and the uniaxial compressive strength (UCS) with point load index Is(50). Additionally, the second factor (~27% of the total data variability) correlates physical properties such as w, nt, physicochemical properties such as the methylene blue test (MBF), mechanical properties such as UCS, Is(50), and loss on ignition (LOI), which highlights the effect of mineralogy on these properties. Lastly, Factor 3 (~14% of the total data variability) expresses the interdependence of the flakiness index (IF), which is an elongation index (IE) relative to their alteration (LOI).
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Shi, Xiao Chen, Masatoshi Ando, Yuji Kashima, and Katsuyuki Kida. "Crack Observation of PPS Polymer Thrust Bearings under RCF Test in Water." Key Engineering Materials 703 (August 2016): 178–82. http://dx.doi.org/10.4028/www.scientific.net/kem.703.178.
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Polymer bearings are widely used under certain environments due to the advantages on light weight, low friction coefficient, high corrosion resistance and electric insulation. The main reason for polymer bearing failures in water was formation of flakings due to crack propagation. However, the mechanism of fatigue crack propagation in polymer material under rolling contact condition has not been clearly explained yet. In the present study, detailed crack observations were made on cross sections along both radial and rolling directions after RCF (Rolling Contact Fatigue) test in water using PPS thrust bearings.
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Firdaus, Firdaus, Yuhanis Yunus, and Muhammad Isya. "KARAKTERISTIK CAMPURAN AC-WC MENGGUNAKAN AGREGAT SIMEULUE DENGAN VARIASI ASPAL RETONA BLEND 55 DAN ASPAL PENETRASI 60/70." Jurnal Teknik Sipil 1, no. 3 (January 15, 2018): 605–16. http://dx.doi.org/10.24815/jts.v1i3.9999.
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Abstract: Asphalt concrete pavement is depend on the type and composition of aggregate, asphalt, and filler being used. In this study, the aggregate used was an aggregate of Simeulue Island. In this Regency are difficult to find enough hard aggregate because the majority of the rocks there come from the process of particles mineral deposition, rest of the animals and plants which are found in the River (Aribowo, 2014). This research was conducted to find out the level of asphalt mixtures resistance using Simeulue aggregate with asphalt variation percentage of retona blend 55 and pen. 60/70 as a binder. This research begins with an examination of the physical properties of asphalt and aggregate next manufactured specimens based on gradations planning to determine of optimum asphalt content (OAC) with the overlapping method. From the results obtained, the elongation and flakiness index value did not meet the required specifications, those were 35.27% and 14.38%. The soundness aggregate against of Sodium and Magnesium sulfate (Mg2SO4) = 26.43% where is the maximum value required 12%. Aggregate wear value still meets the requirement, that was 23.84% 40%. OAC for AC-WC mixture using 100% RB, 100% Pen, 80% RB/ 20% Pen, 65% RB/ 35% Pen, 50% RB/ 50% Pen. was in the amount of 6.18%; 6.37%; 6.20%; 6.06% and 6.06%. From the Marshall test results in every OAC for all variations of immersion, showed the stability value using RB higher than by using Pen. 60/70. This was because asphalt RB can tie the Simeulue aggregate well compared to asphalt Pen. 60/70. The flow value was higher than the asphalt RB. VIM and MQ value at all immersion variation, using asphalt RB were higher than by using asphalt Pen. The durability value in all types of AC-WC mixture still meets the requirements of the Dept. PU (2010) ≥ 90%. While the durability value of 48-hour immersion already is under 90%.Abstrak: Perkerasan beton aspal sangat tergantung pada jenis dan komposisi agregat, aspal serta filler yang digunakan. Penelitian ini menggunakan agregat dari Kabupaten Simeulue. Pada Kabupaten ini sulit ditemukan agregat yang cukup keras karena mayoritas batuan yang ada berasal dari proses pengendapan partikel mineral, sisa hewan dan tanaman yang terdapat di sungai dan memiliki nilai pelapukan yang tinggi (Aribowo, 2014). Penelitian ini dilakukan untuk mengetahui tingkat ketahanan agregat Simeulue dengan variasi persentase aspal retona blend 55 dan aspal penetrasi 60/70 sebagai bahan pengikat dengan harapan dapat menghasilkan perkerasan yang lebih baik. Penelitian ini diawali dengan pemeriksaan sifat fisis aspal dan agregat selanjutnya dilakukan pembuatan benda uji berdasarkan gradasi rencana untuk menentukan kadar aspal optimum (KAO) dengan metode overlapping. Dari hasil penelitian agregat diperoleh nilai indeks kepipihan dan kelonjongan tidak memenuhi syarat yaitu sebesar 35,27% dan 14,38%. Kekekalan bentuk agregat terhadap larutan NaCl dan MgSO4 = 26,43% dimana nilai yang disyaratkan maksimal 12%. Untuk nilai keausan agregat masih memenuhi syarat yaitu sebesar 23,84% 40%. KAO campuran AC-WC menggunakan 100% RB, 100% Pen. 60/70, 80% RB/ 20% Pen, 65% RB/ 35% Pen, 50% Rb/ 50% Pen, masing-masing sebesar 6,18%; 6,37%; 6,20%; 6,06% dan 6,06%. Dari hasil uji Marshall pada setiap KAO untuk semua variasi rendaman, menujukkan nilai stabilitas menggunakan aspal RB lebih tinggi dibandingkan dengan Pen. 60/70. Hal ini dikarenakan aspal RB dapat mengikat agregat Simeulue dengan baik. Nilai flow lebih tinggi dibandingkan aspal RB. Untuk nilai VIM dan nilai MQ menggunakan aspal RB lebih tinggi dibandingkan dengan Pen. 60/70. Nilai durabilitas pertama pada semua jenis campuran masih memenuhi persyaratan Departemen PU (2010) ≥ 90%. Sedangkan nilai durabilitas kedua sudah berada di bawah 90%.
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KOIKE, Hitonobu, Genya YAMAGUCHI, Koshiro MIZOBE, and Katsuyuki KIDA. "Flaking of PEEK under one-point rolling contact fatigue using Al2O3 ball." MATEC Web of Conferences 264 (2019): 01004. http://dx.doi.org/10.1051/matecconf/201926401004.
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The growth of flaking as tribological fatigue failure in PEEK was investigated through the one-point type rolling contact fatigue test between a machined PEEK polymer shaft and an alumina bearing's ball. Due to Hertzian contact of cyclic compressive stress, the subsurface fatigue cracks in the PEEK shaft propagated in rolling and axial directions. When the rolling fatigue life of the PEEK shaft reached 106 fatigue cycles, many narrow angled cracks occurred in the near-surface of the rolling track without flaking. On the other hand, when the flaking ocuurred on the PEEK shaft before 106 fatigue cycles, semicircular surface and subsurface crack propagations were observed. From these observations, it was found that micro-flaking occurred due to the linkages between subsurface and surface cracks. Flakingdeveloped due to the accumulation of these micro-flakings.
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Morán, Jesús, Cristian Augusto, Antonia Bertolino, Claudio De La Riva, and Javier Tuya. "FlakyLoc: Flakiness Localization for Reliable Test Suites in Web Applications." Journal of Web Engineering, June 3, 2020. http://dx.doi.org/10.13052/jwe1540-9589.1927.
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Web application testing is a great challenge due to the management of complex asynchronous communications, the concurrency between the clients-servers, and the heterogeneity of resources employed. It is difficult to ensure that a test case is re-running in the same conditions because it can be executed in undesirable ways according to several environmental factors that are not easy to fine-grain control such as network bottlenecks, memory issues or screen resolution. These environmental factors can cause flakiness, which occurs when the same test case sometimes obtains one test outcome and other times another outcome in the same application due to the execution of environmental factors. The tester usually stops relying on flaky test cases because their outcome varies during the re-executions. To fix and reduce the flakiness it is very important to locate and understand which environmental factors cause the flakiness. This paper is focused on the localization of the root cause of flakiness in web applications based on the characterization of the different environmental factors that are not controlled during testing. The root cause of flakiness is located by means of spectrum-based localization techniques that analyse the test execution under different combinations of the environmental factors that can trigger the flakiness. This technique is evaluated with an educational web platform called FullTeaching. As a result, our technique was able to locate automatically the root cause of flakiness and provide enough information to both understand it and fix it.
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Ahmad, Azeem, Ola Leifler, and Kristian Sandahl. "Empirical analysis of practitioners' perceptions of test flakiness factors." Software Testing, Verification and Reliability, August 24, 2021. http://dx.doi.org/10.1002/stvr.1791.
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Verdecchia, Roberto, Emilio Cruciani, Breno Miranda, and Antonia Bertolino. "Know You Neighbor: Fast Static Prediction of Test Flakiness." IEEE Access, 2021, 1. http://dx.doi.org/10.1109/access.2021.3082424.
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Maharjan, Dev Krishna, and Naresh Kazi Tamrakar. "Quality of siltstones for concrete aggregate from Nallu Khola area, Kathmandu valley." Journal of Nepal Geological Society 30 (December 1, 2004). http://dx.doi.org/10.3126/jngs.v30i0.31708.
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The siltstones of the Tistung Formation are the major source of concrete aggregate in the Kathmandu valley. A member of quarries are operating in the valley, especially in the vicinity of the Nallu Khola, for more than three decades. Randomly collected siltstone samples from both banks of the Nallu Khola were studied to reveal their petrography and chemical composition. Crushed rock fragments were investigated to determine their overall aggregate properties. Tests were carried out to determine shape, flakiness index, elongation index, degree of induration, Schmidt hammer value, dry density, water absorption value, aggregate crushing value, and aggregate impact value. The test results indicate that the aggregates are physically, mechanically, and chemically sound.
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Mahmud, Mohd Zul Hanif, Haryati Yaacob, Ramadhansyah Putra Jaya, and Norhidayah Abdul Hassan. "Laboratory Investigation on the Effects of Flaky Aggregates on Dynamic Creep and Resilient Modulus of Asphalt Mixtures." Jurnal Teknologi 70, no. 4 (September 9, 2014). http://dx.doi.org/10.11113/jt.v70.3498.
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This paper presents an investigation on the effects of flaky aggregates in asphalt mixture. In general, aggregate characteristics are critical to the performance of asphalt mixture. Therefore, flaky aggregate is normally avoided simply because it has significant contribution towards the gradation and reduces the interlocking characteristics of aggregates within asphalt mixture. In practice, it is recommended that the amount of flakiness aggregate should be limited to 25% or less. This study evaluates the mechanical properties of asphalt mixture specimens prepared with various percentages of flaky aggregates particularly 10%, 20% and 30% by the total weight of the mixture. Several laboratory tests were conducted including Marshall properties test, Indirect Tensile Modulus test and Dynamic Creep test. The results show that higher bitumen content is required with the increased in the amount of flaky aggregates added to mixture. Furthermore, greater amount of flaky aggregates tends to reduce the mixture’s resilient modulus and its resistance against permanent deformation.
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Czinder, Balázs, and Ákos Török. "Strength and abrasive properties of andesite: relationships between strength parameters measured on cylindrical test specimens and micro-Deval values—a tool for durability assessment." Bulletin of Engineering Geology and the Environment, October 15, 2020. http://dx.doi.org/10.1007/s10064-020-01983-9.
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Abstract Aggregates are necessary materials for the construction industry. Owing to their favourable properties, andesites are frequently used rock materials; hence, the investigation of their mechanical and aggregate properties has great significance. This paper introduces the analyses of 13 Hungarian andesite lithotypes. The samples were collected from six andesite quarries in Hungary. Cylindrical specimens and aggregate samples with 10.0/14.0-mm-sized grains were made from rock blocks. The specimens were tested in dry, water-saturated and freeze–thaw subjected conditions. Bulk density, uniaxial compressive strength, modulus of elasticity, indirect tensile strength and water absorption were measured. The abrasion resistance was tested by micro-Deval tests. The flakiness indexes of the samples were also measured. The data set of the laboratory test results provided input for further, one- and two-variable statistical analyses. According to the test results, there is no significant difference between the strength parameters measured in water-saturated and in freeze–thaw subjected conditions. The correlation and regression analyses revealed relationships between some rock mechanical parameters, as well as between micro-Deval coefficient and uniaxial compressive strength.
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Mishra, Anjay Kumar, Dinesh Gupta, and P. S. Aithal. "Factors Identification and Conformance of Quality of Cement and Coarse Aggregate used at Gautama Buddha Airport Upgrading Component, Nepal." International Journal of Management, Technology, and Social Sciences, October 5, 2020, 187–200. http://dx.doi.org/10.47992/ijmts.2581.6012.0113.
Full textAbstract:
Quality management system has been challenging in construction of airport project. The objective of study is to assess the factors affecting quality and conformance of Cement and Coarse Aggregate standard used at Construction Site of Gautam Buddha Airport Upgrading Component. This research is based on key informant interview with supervisor and site engineers, questionnaires survey with clients, consultants and contractors who were involved in airport construction projects along with lab test of cement and coarse aggregate of airport construction sites. Statistical tools mean value and relative importance index were used for the ranking of different quality methods. Airport follows specification and standard technical guidelines for the airport construction work. The major factors affecting the quality management in airport construction was Unavailability of competent staff, Low quality drawing and specification and Poor-quality procedure and department for ensuring quality assurance practice Provide training and seminar on quality assurance and Support the setting up of of cube of 3 days, 7 days and 28days is18.8N/mm2 (>16N/mm2), 27.20N/mm2 (>22N/mm2) and 39.40N/mm2 (>33N/mm2) respectively. The average initial setting Time and final setting time of cement is 180 min(>45min) and 351 min(<600min) respectively and average soundness of cement is 2.7mm(<10mm). The test for aggregate, it was found that average Los Angeles Abrasion value of aggregate was 32.8%(<40%), average crushing value of aggregate was 19.88%(<25%), Flakiness index of aggregate found that 19.85%(<25%) and the gradation of aggregate was found that within specification. Quality in airport construction starts from selection of material, inspection, tests employed.